1 | /* |
2 | * Copyright (C) 2012, 2013 Apple Inc. All Rights Reserved. |
3 | * |
4 | * Redistribution and use in source and binary forms, with or without |
5 | * modification, are permitted provided that the following conditions |
6 | * are met: |
7 | * 1. Redistributions of source code must retain the above copyright |
8 | * notice, this list of conditions and the following disclaimer. |
9 | * 2. Redistributions in binary form must reproduce the above copyright |
10 | * notice, this list of conditions and the following disclaimer in the |
11 | * documentation and/or other materials provided with the distribution. |
12 | * |
13 | * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY |
14 | * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
15 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
16 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR |
17 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
18 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
19 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
20 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
21 | * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
22 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
23 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
24 | * |
25 | */ |
26 | |
27 | #include "config.h" |
28 | #include "DocumentSharedObjectPool.h" |
29 | |
30 | #include "Element.h" |
31 | |
32 | namespace WebCore { |
33 | |
34 | inline unsigned attributeHash(const Vector<Attribute>& attributes) |
35 | { |
36 | return StringHasher::hashMemory(attributes.data(), attributes.size() * sizeof(Attribute)); |
37 | } |
38 | |
39 | inline bool hasSameAttributes(const Vector<Attribute>& attributes, ShareableElementData& elementData) |
40 | { |
41 | if (attributes.size() != elementData.length()) |
42 | return false; |
43 | return !memcmp(attributes.data(), elementData.m_attributeArray, attributes.size() * sizeof(Attribute)); |
44 | } |
45 | |
46 | Ref<ShareableElementData> DocumentSharedObjectPool::cachedShareableElementDataWithAttributes(const Vector<Attribute>& attributes) |
47 | { |
48 | ASSERT(!attributes.isEmpty()); |
49 | |
50 | auto& cachedData = m_shareableElementDataCache.add(attributeHash(attributes), nullptr).iterator->value; |
51 | |
52 | // FIXME: This prevents sharing when there's a hash collision. |
53 | if (cachedData && !hasSameAttributes(attributes, *cachedData)) |
54 | return ShareableElementData::createWithAttributes(attributes); |
55 | |
56 | if (!cachedData) |
57 | cachedData = ShareableElementData::createWithAttributes(attributes); |
58 | |
59 | return *cachedData; |
60 | } |
61 | |
62 | } |
63 | |